Abstract
We made a dimensional analysis of Einstein's fields equations in vacuum. To obtain an homogeneous equation we had to take the cosmological constant as the inverse of the square of a length,and immerse our three dimensional curved universe in a four dimensional space. Time is taken as an extra parameter which results to be linked to the fourth dimension of the space in which our universe is embedded. The conclusion is that dark energy in vacuum is linked to dark matter. The same dimensional analysis links matter (or mass) to time and to one dimension in our universe. This may help to find the Higgs boson.